This post shows how to start with Microsoft Flow. This article also expect you to be familiar with SharePoint Online or Office 365 SharePoint. The might be other better way to get started. This is what I have been trying and I am sharing it with you.
I have a SharePoint List only with 2 columns. One Title, Text field, another Price, Number field. You can see Flow on top of the list.
Click on Flow then click Create a flow.
Choose Send a customized email when a SharePoint list item is added.
Click Create Flow.
Click the <- arrow,
Click the Edit.
Click on … then select Delete for Send Email.
Click on … then select Delete for Get my profile
Click New Step.
Under the Actions select Condition.
Select Price for list item. Condition choose is greater than. Condition enter 10.
If Yes then choose Send an email.
Enter the Email address in To, Subject, and Body. Click Save.
Click Save & Test.